Elevated PABPC4 expression in human prostate cancer tissues predicts adverse clinical outcomes.

Background: Poly(A) binding protein cytoplasmic 4 (PABPC4) has been regarded as a prognostic marker in many malignancies. In this study, we evaluated PABPC4 expression at both messenger ribonucleic acid (mRNA) and protein levels. The prognostic value of PABPC4 in patients with prostate cancer (PCa) was also investigated. Methods: The Cancer Genome Atlas (TCGA) database, Gene Expression Omnibus (GEO) database, our analysis of Chinese Prostate Cancer Genome and Epigenome Atlas (CPGEA), and 65 pairs of ribonucleic acid (RNA) sequencing data from our center were employed to detect the expression of PABPC4 in PCa tissues. Tissue microarrays (TMAs) were utilized to detect the expression of the PABPC4 protein, and survival analysis as well as risk factor analysis were conducted. Results: In the 65 pairs of sequencing data, the expression of PABPC4 in tumor tissues was significantly higher than that in paired adjacent tissues (P<0.001), and its expression also presented significant differences among different Gleason groups (P=0.041). In the CPGEA data, the expression of PABPC4 in tumor tissues was significantly higher than that in control tissues (P<0.001), and the expression of PABPC4 in M1 patients was higher than that in M0 patients, although no significant statistical difference was shown (P=0.051). In the TCGA data, the expression of PABPC4 in tumor tissues was significantly higher than that in control tissues (P<0.001). The expression of pT3/4 (pathological tumor stage 3 and pathological tumor stage 4) in high-stage tumor tissues was significantly higher than that in low-stage tumor tissues (pT2) (P=0.02), the expression of pT3/4 in GSE21034 and GSE32571 tumor tissues was significantly higher than that in control tissues (P<0.001), and the expression of pT3/4 in primary tumor tissues was higher than that in metastatic tissues in GSE6752 (P<0.001). The TCGA data revealed that patients with high PABPC4 expression had poorer overall survival (OS) than those with low PABPC4 expression (P=0.04), and the TMA data indicated that patients with high PABPC4 expression had a poor prognosis (P=0.004). Conclusions: Our study demonstrated that PABPC4 was overexpressed at mRNA and protein levels in PCa. We found that patients with high PABPC4 expression had a shorter biochemical recurrence (BCR)-free survival and OS, showing its value as a prognostic biomarker in patients with PCa.